$\left(a+3\right)\left(a+4\right)$

$\int\frac{2x}{x^2\left(x-3\right)}dx$

$\int\frac{2x+21}{2x^2+9x-6}dx$

$\frac{x^{2}-5x+4}{x-3}$

$9y+4y$

$-10-16-1-1-10$

$-\frac{sin\left(t\right)}{1-cos\left(t\right)}+\frac{sin\left(t\right)}{1+cos\left(t\right)}=-\frac{2}{tan\left(t\right)}$